The field of the invention is that of telecommunications, and more specifically that of IP/MPLS (Internet Protocol/Multi-Protocol Label Switching) core and collect networks.
The context of the invention is more particularly an IP/MPLS network whose border routers, also known as edge routers, are meshed by explicit MPLS paths.
Such explicit MPLS paths are known as MPLS Traffic Engineering Label Switched Paths (MPLS-TE LSP).
An MPLS-TE LSP is a connection that starts at a head router (also known as an Ingress router), passes through links and routers referred to as transit routers, and terminates at a destination router (also known as an Egress router).
These paths are set up by the Resource Reservation Protocol-Traffic Engineering (RSVP-TE) signaling protocol defined in the Internet Engineering Task Force (IETF) document Request For Comments (RFC) 3209.
This protocol routes and distributes labels and reserves resources along the path.
The MPLS-TE technology is not described here. For more information see the above document RFC 3209.
Services having high demand in terms of end-to-end availability require deterministic rerouting within less than 50 milliseconds in the event of link or node failure.
This applies in particular to voice over IP (VoIP) services and telemedicine services.
The invention is more particularly directed to a rerouting mechanism that can be activated in the event of failure of the destination router (Egress router) or failure of the connecting link between that destination router and the last transit router to which it is connected.